Option 5 of Mitchell Williams' Immigration Series on alternatives to H-1B visas: Employment-Based Green Card
A U.S. employer will typically start permanent residency (“green card”) sponsorship for a foreign worker after that worker begins working with H-1B status, but it is worth noting that this is not a prerequisite. A U.S. employer may start the employment-based green card process for a foreign worker at any time.
Given the difficulties of obtaining a H-1B visa in the lottery, it may be beneficial for a U.S. employer to start the employment-based green card process when the foreign worker, in particular those foreign workers not born in India or China, is working with Optional Practical Training (OPT), or when the foreign worker has or is eligible for an OPT STEM extension. In some circumstances, it could be possible to complete the process of sponsoring a foreign worker for an employment-based green card within one to two years, but given the complexities it is best to begin planning early as possible.